GMC 1976 ZEO 6083 Maintenance Manual page 639

12- 34 CHASSIS ELECTRICAL
1 . Turn radio on . Switch to AM band if radio is
AM-FM.
2 . Tune in a weak station at approximately 1400
kilohertz on the AM band and turn volume control
to maximum .
3 . Adjust antenna trimmer, located behind right
control knob ring, for maximum volume . Access to
antenna trimmer is gained by removing right control
knob and ring and inserting screwdriver to adjust
screw (figure 48).
NOTE :
If, during adjustment, the station
becomes strong so that a change in volume can-
not be heard with further screw rotating, tune to
a weaker station and continue the adjustment .
ANTENNA MAST REPLACEMENT
If it becomes necessary to remove the antenna
mast assembly, refer to Figure 49 for proper part
positioning of mast components .
NOTE :
Antenna cable passes through center
windshield support as shown in Figure 27 .
BALANCE ADJUSTMENT
(AM-FM STEREO MODELS ONLY)
If the sound appears to be louder on one side of
the vehicle than the other, and adjustment to the
audio balance may be made .
NOTE:
On some stereo programming, it is nor-
mal for one side to be louder than the other for
a short time . This is done purposely for stereo
effect. The only positive method to tell if the
balance control needs adjustment is to tune in a
non-stereo program and make a critical evalua-
tion .
A- 181 7
Figure 48-Antenna Trimmer Adjustment
STEREO TAPE PLAYER
MAST & NUT ASM .
MOUNTING NUT
WASHER
GASKET
SEAL
BODY COLLAR &
LEAD IN ASM.
Figure 49-Antenna Mast Installation
If adjustment is needed proceed as follows :
1 . Turn radio on . Switch to AM band .
A-1818
2. Remove left knob, spring and control ring to
gain access to stereo balance screw.
3 . With fader control turned fully clockwise, in-
sert screwdriver into balance screw .
4. Rotate balance control adjustment clockwise
or counterclockwise until the sound in the left and
right speakers appears to have equal volume .
5 . Install left control ring, spring and knob .
The only required maintenance on tape players is
periodic cleaning of the tape player head . This ser-
vice should be performed approximately every 100
hours of operation. If the tape slips and runs slowly,
the capstan (revolving metal post), head and tape
guide should be cleaned with a cotton swab mois-
tened with alcohol. To clean capstan, trip the on-off
switch at the rear of the receptacle and hold the swab
against the rotating capstan .
No lubricants should be used since they will
cause the player to operate improperly, especially at
extreme temperatures .